D.C. joined the guys on TMZ Sports (weeknights on FS1) ... when he was asked if he'd ever want another crack at J.J. in the Octagon (whenever Bones is allowed to fight) ... despite everything that went down. "That's the craziest thing about the whole situation. Competitively, he's beaten me twice. So yeah, of course. People think I'm insane for it." There is a catch. D.C. says there can't be any cheatin' ... the playing field has to be level.Big fan of Kareem Hunt's insane debut on Thursday? Thank the Dallas Cowboys ... so says Michael Irvin. The Playmaker was clearly impressed with the rookie RB after the Chiefs put the smackdown on Tom Brady and the Patriots ... telling TMZ Sports the dude WENT OFF! So, how do the Cowboys fit in? "What you will see now is more guys getting opportunities because of what the young guys like Dak Prescott and Ezekiel Elliott did," Irvin explained. Dak and Zeke got the keys to the Cowboys kingdom as rookies last year and lit it up -- and now Irvin says other teams are willing to take a chance on starting rooks in the hopes of recreating the same magic.Kevin Hart opened up about cheating last year, and said he wouldn't do it ... not because it's wrong, but because the chances are he'd get caught. It's pretty stunning in the wake of Kevin's claim he's being extorted over video showing him and a woman getting super cozy and another video which makes it appear a sexual encounter is about to go down. Quick to point out ... in the prelude to sex video you don't see Kevin. Hart told The Breakfast Club in January, 2016, social media combined with thots makes cheating a sexual form of Russian Roulette. As we reported, Kevin has contacted cops claiming someone has tried to extort him with the video. He's not denying its him in some of the various clips.Kim Porter is definitely Team Matt Barnes -- telling TMZ Sports it's NEVER okay to bang your friend's ex-wife ... "especially if you're ball players!" Diddy's baby mama was leaving Mastro's in Bev Hills when we asked about the Barnes vs. Derek Fisher situation ... something she has a VERY strong opinion about. Check out the clip ... Porter says Fisher was "dead wrong" -- and sums up her opinion about the NY Knicks coach in 3 words: "Trifling, trifling and more trifling."Teairra Mari just had her Uber beatdown case dropped ... because the driver refused to take the stand. Prosecutors moved to dismiss 3 charges against the "Love & Hip Hop: Hollywood" star for allegedly beating the hell out of a driver and stealing his charger ... the judge agreed and tossed the case. More good news for Mari ... according to court docs, her $26k bail money was returned. You'll recall ... Mari was a wanted woman this past summer when she was a no-show in court, but she got her act together and surrendered to cops. As for why the driver flaked ... Mari's attorney, Lonnie Brandon, tells us the driver knew his story wouldn't hold water. Either way ... Mari's a free woman again. We're also guessing she switched to Lyft.Jon JonesСЏв•—в”ђ can deny it all he wants ... but he cheated before BOTH his fights with Daniel Cormier, which makes DC the true champ -- so says UFC superstar Luke Rockhold. The "B" sample for Jones' failed drug test came out on Tuesday ... which revealed a positive test for the same banned steroid he got popped for last month. Now, Luke says it's time we all faced the truth."People can be in denial about Jon ... but he's taken things all along the way. And that's what USADA's here for -- to clean up the cheaters." Rockhold feels terrible for his BFF, Cormier, and Jones too -- calling the whole situation "unfortunate" -- but told TMZ Sports he's not dwelling on it cause he's got a huge comeback fight this weekend.No ruling yet ... but it's close. The NFL Player's Association has said the arbitrator overseeing Ezekiel Elliott's appeal of his 6-game suspension was trying to issue his decision by end of business day on Tuesday -- but so far, nothing yet. The operative word in that sentence is "trying" -- we're told the arbitrator has a lot of material to comb through and wants to be thorough ... he doesn't want to rush out a decision. Meanwhile, Ezekiel appeared in a courtroom in Sherman, Texas where he filed documents in federal court asking for a restraining order against the NFL, barring the league from enforcing punishment stemming from the domestic violence investigation.